Production of biosurfactant rhamnolipid optimized
Biosurfactants are surfactants biologically produced by microorganisms, presenting several advantages when compared to synthetic surfactants. Pseudomonas aeruginosa is known for producing rhamnolipids, considered one of the most interesting types of biosurfactants due to their high yields, when compared to other types.
In a recent study published by Camara and co-workers, the production of rhamnolipid from P. aeruginosa was optimized. At first, the Plackett–Burman design was used to select most significant variables affecting the biosurfactant production yield among nine variables—carbon–nitrogen ratio, carbon concentration, nitrogen source, pH, cultivation time, potassium and magnesium concentrations, agitation, and temperature. Then, using main variables, a central point experimental design aiming to optimize rhamnolipid production was performed. The maximum biosurfactant concentration obtained was 0.877 mg L−1. The rhamnolipid also displayed a great emulsification rate, reaching approximately 67%, and the ability to reduce water surface tension from 72.02 to 35.26 mN m−1 at a critical micelle concentration (CMC) of 127 mg L−1, in addition to presenting a good stability when exposed to wide pH and salinity ranges. The results suggest that rhamnolipids are promising substitutes for synthetic surfactants, especially due to lower impacts on the environment.
The paper has been published in Journal of Surfactants and Detergents, April 2019 https://doi.org/10.1002/jsde.12287